Re: Arcs anyone?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Bill Vance <ccq@x> wrote:

> From time to time I come across references to something called arc

minutes and

> arc seconds. Are these ever used in machining, or CNC? What are

they, anyway?

When programming a CNC, decimal degrees are used instead of Degrees,
minutes, and seconds.

60 degrees 15 minutes 30 seconds would convert to:

60.0 degrees + 15/60 degrees + (30/60 minutes)/60 degrees

=60.00000 + .25000 + .00833 = 60.25833 degrees.

Most CNC rotary tables are only accurate to 3 decimals, hence 60.258
degrees is "TRULY, REAL" close.

To put it a bit more into perspective .001 degree, (the minimum
programming increment with a 3 place decimal degree), is equal to
3.6 Arc-seconds. If you need something finer than that, you are
probably on the wrong list.

Fred Smith - IMService
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